Numbers 31:17 KJV
Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.
Numbers 31:17, King James Version
In context
16 Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against the Lord in the matter of Peor, and there was a plague among the congregation of the Lord.
17 Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.
18 But all the women children, that have not known a man by lying with him, keep alive for yourselves.